Various types of fasteners have been used for attaching disposable absorbent articles, e.g., baby diapers, incontinence diapers or the like, around the user's waist. Exemplary fasteners are adhesive tape fasteners and mechanical tape fasteners. Adhesive fastener systems allowing tape ends to be repeatedly fastened, unfastened and re-fastened have been available on the market since the beginning of the 1980s. One adhesive tape fastener system of this type is described in U.S. Pat. No. 5,024,672.
Analogous to adhesive tape fastener systems and adhesive tape fasteners are mechanical tape fastener systems and mechanical tape fasteners to define fastener systems and fasteners. In such mechanical systems and fasteners, the bond is effected not by adhesive means but by means of mechanical interlocking between hooks disposed on one of the parts of a fastening known as a hook-and-loop fastener and loops, apertures or fibre filaments disposed on the other hook-and-loop fastener part.
In most respects, modern adhesive tape fastener systems function satisfactorily. However, a serious problem is the deteriorated quality of the adhesion, should, e.g., talcum powder or baby oil be spilled onto the pressure-sensitive adhesive substance or onto the bonding face to which the tape is to be attached. This problem may be removed by using mechanical tape fastener systems. In addition, consumers want disposable absorbent articles that are soft to the touch and have a textile-like appearance as opposed to the plastic films of which outer layers of disposable absorbent articles were predominantly formed. Hitherto, mechanical tape fastener systems have been too expensive to compete with adhesive tape fastener systems. In recent years novel mechanical tape fastener systems have been developed that are more price-competitive. This fact in conjunction with the increasing use of textile-like outer layers and elimination of the problems caused by spillage on the bonding faces, has contributed to manufacturers of disposable absorbent articles using mechanical tape fastener systems more.
By applying mechanical tape fasteners on both sides of, e.g., the rear end portion of a diaper, and providing a complementary bonding face on the external face of the opposite end of the diaper in a manner corresponding to that described in U.S. Pat. No. 5,024,672, the problem of fastening of the diaper as it is being put on, unfastening it and refastening thereof is solved. Such a mechanical tape fastener system is also described in, e.g., EP-A1-0324578. This publication also touches on the problem involved in sealing a used diaper such that it forms a closed package for reliable enclosure of feces inside the diaper, and the publication describes one means of solving this problem.
The latter publication mentions the problem arising because the mechanical tape fastener may unintentionally hook onto parts of the diaper before attachment to the intended bonding face has been made.
Over the years, the permanent anchorage of tape fasteners has been subject to much development, and many suggested solutions have been presented in the patent literature. This is also true of the problem of protecting the bonding face of the tape fasteners from unintentionally adhering where not wanted before the diaper is put on. The tape fasteners, which are anchored to the article by the producer in the process of the manufacture of the article, are exposed to considerable stress as the diaper is being put on and the forces arising in connection therewith are absorbed by the point of anchorage. If the tape fastener is attached to the external layer of the article only, there is a risk that this layer be torn as the article is being put on. This problem is discussed in U.S. Pat. No. 3,867,940, and the solution suggested therein is to reinforce the external layer in the area of the point of anchorage.
The solution most predominantly found on the market and also in the patent literature is the use of the so-called Y-tape, which comprises two branches that are applied about the edge portion of the diaper, with one branch on the external layer and the other on the inner layer, thus making use of the inherent strength of the inner as well as of the external layer. The above publication EP-A1-0324578 and WO 95/05140, e.g., disclose a Y-tape designed for mechanical tape fasteners.
One disadvantage inherent in Y-tapes is that they have to be attached during manufacturing on both sides of an edge portion of a disposable absorbent article, such as a diaper. The manufacturing utilizes a web travelling at a very high speed, a feature that makes the application of Y-tapes very complex. A further disadvantage is that the position of tape fasteners, applied around the edge portion of the rapidly advancing web of articles, may lead to serious drawbacks, both as regards the freedom of changing the manufacturing process and the freedom of changing the article itself.
Another prior-art solution is the so-called Z-folded tape, which is anchored permanently to the external face of the outer layer of the article. A Z-folded tape is shown, e.g., in U.S. Pat. No. 4,576,598. A drawback inherent in Z-folded tapes is that they are attached to the external face of the outer layer of, e.g., a diaper. The result is that the Z-tape, once attached, is unprotected during the subsequent processing steps, which usually include cross-cutting, cross-folding and insertion in a bag. To some extent this is applicable also to diapers comprising Y-tapes.
In the storage condition of the article, i.e., before it is used, adhesive and hook-on fastening parts on the tape fasteners should be safely covered in order to prevent unintentional hook-on or adhesion that makes handling of the article more difficult as the latter is being put on. Hitherto, this problem usually has been solved by ensuring that in the storage condition of the tape fasteners, adhesive parts on the fasteners, including mechanical tape fasteners, abut against release-agent coated plies of material. A solution of this kind is described for instance in the above mentioned EP-A1-0 324 578. Release-agent coatings are, however, comparatively expensive while at the same time they often require the provision of an additional layer of material in the tape fastener, which makes the design of the latter more complex. When mechanical tape fastener systems are used, it is conceivable to arrange for the mechanical bonding faces of the tape fastener, in the storage condition of the latter, to abut against and be mechanically interconnected with a part of a hook-and-loop fastener that is complementary to said bonding face. If a safe interconnecting bond is wanted, a solution of this kind requires the provision of complementary bonding faces for all mechanical fasteners of the article, with resulting increased material costs for and a more complex manufacture of said article.